In one aspect this invention relates to the mounting of wheels on vehicles. In a further aspect this invention relates to the mounting of wheels which are a portion of a track laying system.
Vehicles which are track laying vehicles generally have an endless track which is constantly driven in the direction the vehicle is to move. The upper portion of the track is supported on a series of idler wheels and the track is driven by a driving wheel or cog. The lower portion of the track is contacted by the vehicles road wheels which support the vehicle as the vehicle moves over the terrain. The road wheels are attached to the vehicles' hull by means of a road wheel arm and rotate freely on an axle through the wheel's center. The road wheel arm has one end connected to the road wheel axle and the other end connected to a torsion bar. The torsion bar is rigidly mounted to the vehicle hull at the end of the bar distal the end attached to the road wheel arm. Generally the road wheel axle is mounted below the point where the torsion bar is attached to the hull. The resulting axle-road arm-torsion bar structure is similar to a crank with one arm of the crank rigidly fixed to the vehicle hull. When the road wheel moves vertically the road wheel arm will move vertically in a plane perpendicular to the longitudinal axis of the torsion bar thereby applying a torsional force to the end of the torsion bar attached to the road arm. Since the other end of the bar is fixed to the hull, the bar resists the torsional force providing a spring like action as is well known in the torsion bar art.
The torsion bar system has proved to be a good method of attaching road wheels to the hull of track laying vehicles. However such vehicles are subject to the application of explosive upward forces to the tread such as when the vehicle drives over a mine or strikes a similar explosive device. Such explosive forces cause sufficient damage to the road wheel to require replacement of the road wheel.
The explosive forces applied to the track generally cause a substantial bending force to be applied to the road wheel arm at an angle to the plane in which the road wheel arm normally moves. The resulting bending moment when transmitted to the torsion bar causes a permanent deformation in the torsion bar. Because the torsion bar is located within a support structure, a bend in the bar makes repair and replacement difficult and requires that the entire road wheel mounting assembly to be removed from the hull to effect a repair.
It would be desirable to provide a road wheel assembly with a mounting structure which allows vertical movement of the wheel in a plane transverse to the torsion bar axis but which will fail at a location between the road wheel and the torsion bar to prevent torsion bar bending or failure. This will decrease the time necessary to repair a damaged road wheel assembly and obviate the need to remove the entire mounting from the hull. Such a structure would allow road wheel repair under field conditions and with a minimum of tools.